Chris Brown and Rihanna are a couple again, but how long will it last? / AFP/Getty Images

by Maria Puente, USA TODAY

by Maria Puente, USA TODAY

Why are stars attracted to bad boys? Or, put another way, why are bad boys attractive, and not just to stars?

This comes up, again, in the wake of news that pop star Rihanna, 24, has chosen to get back together with R&B singer Chris Brown, 23, the bad-boy boyfriend who beat her up four years ago. Not only is she not sheepish, she's defending herself, in the pages of Rolling Stone, with candor, gusto and even a measure of maturity.

"I wasn't going to let anybody's opinion get in the way of it," Rihanna told the magazine. "Even if it's a mistake, it's my mistake. After being tormented for so many years, being angry and dark, I'd rather just live my truth and take the backlash."

They will mark their return as a couple by walking the red carpet together Sunday at the Grammy Awards (both are nominated and Rihanna will be performing), reports HollywoodLife.com. They spent five hours together in a recording studio Tuesday night into Wednesday morning, photographed as they drove away in his black Porsche. And on Wednesday, they went to court in Los Angeles together; she blew him a kiss as he entered the courtroom, and they left together after a brief hearing.

Brown was back in court to deny accusations this week that he did not complete the community service he was required to do as punishment in the Rihanna assault case. He could see his probation revoked, but the judge asked for additional reports and scheduled another hearing in April.

Brown is not a bad guy, Rihanna insists. "There's so many reasons why I ever reconsidered having him in my life," she said in the Rolling Stone interview. "He's not the monster everybody thinks. He's a good person. He has a fantastic heart. He's giving and loving. And he's fun to be around."

Brown has repeatedly apologized. His first was a two-minute video on his official YouTube page apologizing to fans and Rihanna, expressing remorse and his "deepest regret" and saying he had repeatedly apologized to Rihanna and "accepts full responsibility." But now he's just mad, ranting on his Instagram page Tuesday that he was "sick of being accused" and "I honestly think I deserve respect."

Rihanna and Brown aren't the first good-girl/bad-boy celebrity relationship and won't be the last. Recall the ups and downs of Whitney Houston and her husband, Bobby Brown, a marriage in which both parties behaved badly at times but nevertheless lasted longer than anticipated.

Still, many have reacted to Rihanna with horrified incredulity. How could she?

"I can't think of a worse message to send to young people," says PR expert Howard Bragman, vice chairman of Reputation.com. "You can't do crisis publicity and not believe in forgiveness, OK? But all you have to do is look at this guy's life and his actions, and realize he's the same hot-tempered guy. ... I think she is in real jeopardy."

But the secondary reaction is more ambivalent, including from professional relationship experts: Don't heap opprobrium on the girl just yet, because maybe her choice is not as inexplicable as it seems. And maybe lots of other women, famous and non-famous, would do the same thing.

"Someone has to be the good guy and the bad guy in our culture, but the truth is there is no such thing because people change," says Ian Drew, entertainment director for Us Weekly, who recently spent a week covering Rihanna on tour. "If she feels she knows him better than we do, then we need to support her."

In fact, what might seem from the outside like a toxic relationship is "usually more complicated," says Delrita Abercrombie, clinical psychologist at Brookdale University Hospital in Brooklyn, who teaches a course on women's psychology and works with women in abusive relationships. Rihanna and Brown "have a lot in common, and both need help with anger management, but that doesn't mean they just scrap their relationship because they're not able to master it yet. ...They need to figure out how to be together without hurting each other."

Everybody knows of at least one toxic relationship, either in their own lives or from the pages of celebrity media, going back to Liz Taylor and Dick Burton or Ike and Tina Turner, and as recent as Mel Gibson and Oksana Grigorieva, Charlie Sheen and ... well, too many to list here.

Sheen, for instance, can be a very bad boy, moving from bullying and belligerence to baffling buffoonery in the space of minutes. Yet, he has no trouble getting women, no trouble persuading them to marry him, have his children or just clean up after him.

Yes, he's rich, famous, talented and rakishly handsome, but bad boys who are none of these things still get the girl, too. Why is that?

"Celebrities are the same as regular people, and why would a non-celebrity woman stay in a (toxic) relationship? Low self-esteem," says Bonnie Fuller, editor of HollywoodLife.com, which has been following the Rihanna/Brown story closely. "Lots of celebrities have low self-esteem."

Other reasons, say experts, can range from a family history of abuse to cultural conditioning and financial dependency (especially if there are children).

And don't forget the unequal balance of power. "Someone like Charlie Sheen or Mel Gibson is so much wealthier, so much more powerful and connected, so that the sense of powerlessness is more intensified," Fuller says. "But Rihanna is even more wealthy and powerful in the music industry than (Brown). His career was hurt by the (abuse accusations), he had to rebuild it."

Rihanna's career, meanwhile, took off. Will her return to Brown change that? Fans are able to separate the art from the personal life, says Drew; even Brown is still selling, still getting awards (he is nominated for best urban contemporary album on Sunday) and still getting fans.

"We're too judgmental in our culture," Drew says. "If a basket-weaver gets into trouble, am I still going to buy their baskets? Yes, because If I need a basket, I don't really care. And with many musicians, their personal life fuels their art."

Betsy Prioleau, author of Swoon: Great Seducers and Why Women Love Them, which examines great lovers in history (such as Casanova, Lord Byron, etc.), agrees that the "good/bad polarity is artificial because real people are much more complex." She says "nice-with-spice" is alluring to many, but those attracted to repeat abusers are a minority.

"These are damaged women in a whole cluster of ways," Prioleau says. "They probably suffered some abuse early in life, so they associate pain with love because it feels familiar."

Both Rihanna, born on Barbados in the Caribbean, and Brown, born in Virginia, come from families with a history of domestic abuse, Fuller says. Rihanna told ABC in a November 2009 interview that her father beat her mother. In 2006, Brown told MTV News that he watched his mother endure abuse.

"Their situation is unique in Hollywood," Fuller says. "Part of what drew them together was that shared experience, they could understand each other and lean on each other. Psychologists say that when you grow up this way you don't want to repeat the behavior, but that's the learned behavior you have. ... Rihanna says there's no way she would stay if (Brown ever hits her) again. And she genuinely feels it won't happen again, because he wouldn't want it to."

Rihanna's willingness to be open and direct with her fans through social media is notable. As a longtime celeb editor, Fuller says this is a new development in the celeb/fan relationship, and Rihanna is taking advantage to ensure that her fans don't pick up the wrong message.

Celebrities "have an informed and intimate relationship with their fans, a constant conversation, allowing an open window into their lives," Fuller says. "This is a very modern phenomenon, and it kind of changes the game. Fans are going to be much more informed about Rihanna and her thinking than any fans of celebs even five years ago."